Diazonium compounds and diazotype materials containing them



United States Patent ()1 fice 3,520,692 Patented July 14, 1970 3,520,692 DIAZONIUM COMPOUNDS AND DIAZOTYPE MATERIALS CONTAINING THEM Carel Jacobus Knoester and Henricus Maria Wilhelmus Seegers, Limburg, Netherlands, assignors to Chemische Fabriek L. Van Der Grinten N.V., Venlo, Netherlands, a corporation of the Netherlands No Drawing. Filed June 28, 1966, Ser. No. 561,040 Claims priority, application Netherlands, July 2, 1965, 6508566 Int. Cl. G03c 1/54 U.S. CI. 9691 20 Claims ABSTRACT OF THE DISCLOSURE The invention relates to light-sensitive diazonium compounds of a new type and to diazotype material sensitized with these diazonium compounds. This diazotype material may be: so-called one-component diazotype material, which is developed with a liquid containing an azocoupling component, so-called two-component diazotype material, which is developed with the aid of ammonia vapour, or heat-developable diazotype material.

Besides adequate light-sensitivity and suitable coupling activity, diazonium compounds for sensitizing diazotype material should have good stability and give photodecomposition products which are completely or almost completely colourless, which when exposed to light show no staining, or hardly any, and which do not actively react with diazonium compounds to yield dyestuffs.

Diazotype material sensitized with a diazonium compound of insufficient stability has poor keeping quality. Poor keeping quality may appear from a decrease of the concentration of the diazonium compound through gradual decomposition, so that in the course of time copies with azo-dyestuff images of poor density are obtained.

Heat has an accelerating influence on the decomposi tion of diazonium compounds. In practice, diazotype materials are sometimes exposed to temperatures of 4050 C., e.g., during transport in summer. In recent years the interest in heat-developable diazotype material has greatly increased. To be developed, this diazotype material is heated to temperatures between 120 and 180 C. Consequently it is often of great importance that diazonium compounds should have good thermostability.

In recent years very light-sensitive diazonium com pounds have come into use for sensitizing diazotype materials. These compounds are chiefly benzene diazonium compounds having a tertiary amino group in the paraposition with respect to the diazonium group and an etherified hydroXyl group in the meta-position, and possibly a further substituent such as alkoxy, alkyl, or halogen in the para-position with respect to the etherified hydroxyl group.

British patent specification No. 867,629 describes diazonium compounds of the general Formula I:

in which X is an anion, R and R stand for alkyl groups with at most 4 C-atoms, and R for an alkyl group with at most 4 C-atoms or an aralkyl group with at most 7 C-atoms.

British patent specification No. 888,598 describes diazonium compounds of the general Formula II:

lIIrX in which X is an anion, Y is a hydrogen or a halogen atom or an alkyl or alkoxy group, R stands for an alkyl group, R for an alkyl group with at most 3 C-atoms, and R for a cyclohexyl group.

British patent specification No. 919,037 describes diazonium compounds of the general Formula III:

N I 2X in which X is an anion, Y stands for, e.g., a hydrogen or halogen atom or for a methyl, alkoxy, or phenoxy group, R for a substituted or non-substituted phenyl group, and R and R for a substituted or non-substituted alkyl, cycloalkyl, or aralkyl group. R and R together with the nitrogen atom to which they are attached may also form a heterocyclic ring.

Diazotype material manufactured with diazonium compounds of the Formulae I, II and III is very attractive because of its high light-sensitivity. It may be one-component diazotype material or two-component diazotype material. Upon development with weakly alkaline phloroglucinol developers, such one-component diazotype material furnishes copies with brown azo-dyestutf images, and upon development with buffered weakly acid phloroglucinol developers (if the diazonium compound used has sutficiently high coupling activity to allow development with a weakly acid liquid) it yields copies with dark, often even black, azo-dyestuff images.

Among these diazonium compounds those according to g the Formulae II and III in which Y represents an etherified hydroxyl group, form a class apart. They have considerably lower light-sensitivity, but they show higher thermostability, i.e., they are better able to stand up to storage in a warm atmosphere. The other diazonium compounds according to the Formulae I, II and III are very interesting because of their higher light-sensitivity, but their thermostability is too low, so that diazotype materials sensitized with them will not stand up sufficiently to storage in warm rooms. When such materials are stored for some days at temperatures of 40-50 0, they already show a considerable reduction of the diazonium compound concentration. When diazonium compounds according to the above-mentioned formulae are used in heat-developable diazotype material, the copies made with this material often show weak azo-dyestuff images as a result of pyrolysis of the diazonium compound during development.

It is an object of the present invention to provide very light-sensitive diazonium compounds of a new type and to provide diazotype materials sensitized with these compounds, which material does not present the drawbacks described above with respect to the known materials, or presents them to a lesser degree.

According to the present invention there are provided diazonium compounds of the following general Formula IV:

in which X is an anion, R stands for a substituted or nonsubstituted alkyl, branched alkyl, unsaturated alkyl, cycloalkyl or aralkyl group, COR for an acyl group, R for a substituted or non-substituted alkyl, branched alkyl, unsaturated alkyl, cycloalkyl, aralkyl or aryl group, and

for a tertiary amino group, or a saturated heterocyclic ring which, by means of a nitrogen atom forming part of the ring, is attached to the phenyl nucleus carrying the diazonium group. Either or both of the substituents R and R as well as any of R R and R may be nonsubstituted or may carry a substituent at a position thereof normally occupied by a hydrogen atom.

In the above definition the term acyl is to be understood to mean the radical -COR where R may be a hydrogen atom or an organic radical of any of a great variety of types. The term acyl thus has the meaning usually assigned to it in the literature concerning the diazotype process. See, e.g., British patent specifications Nos. 615,774, 347,430, and 539,031.

Very suitable diazonium compounds for sensitizing diazotype materials according to the invention are those which satisfy the general Formula IV, in which X is an anion, R stands for a substituted or non-substituted alkyl, branched alkyl, unsaturated alkyl, cycloalkyl, aralkyl or aryl group, or a substituted or non-substituted alkoxy, branched alkoxy, unsaturated alkoxy, cycloalkoxy, aralkyloxy or aryloxy group, R for a substituted or nonsubstituted alkyl, branched alkyl, unsaturated alkyl, cycloalkyl, aralkyl or aryl group, R for a substituted or nonsubstituted alkyl, branched alkyl or aralkyl group, and R for a substituted or non-substituted alkyl, branched alkyl, aralkyl or cycloalkyl group.

As in the cases of the diazonium compounds according to the Formulae I and II, the diazonium compounds according to the invention are very light-sensitive, and have higher coupling activity and greater thermostability than the corresponding diazonium compounds without the amino-substituent in the ortho-position. With the azocoupling components commonly used in the diazotype process they yield both light-coloured and dark azo-dyestuffs. With polyvalent phenols such as resorcinol and phloroglucinol they couple to form darker azo-dyestufis than do the diazonium compounds of the Formulae I, II and III.

Consequently, diazotype material sensitized with diazonium compounds according to the invention is very light-sensitive, has higher developing speed, and stands up better to high temperatures than comparable diazotype material sensitized with a corresponding compound without the amino-substituent in the ortho-position.

The diazonium compounds according to the invention are suitable for sensitizing one-component diazotype material and two-component diazotype material and, on account of their good thermostability, they are also very suitable for use in heat-developable diazotype material, since their pyrolysis during the development of such material is relatively small.

The diazonium compounds according to the invention which have a light alkoxy group in the meta-position and a light tertiary amino group in the para-position, such as a dimethylamino, diethylamino, di(2'-hydroxyethyl) amino, or a morpholino, piperidino, or pyrrolidino group, are better suited for use in two-component diazotype materials, in which relatively slowly coupling diazonium compounds are generally preferred. On account of their higher coupling activity, the compounds with a N-alkyl- N-aralkylamino group or a N-alkyl-N-cycloalkylamino group in the para-position, as well as those with e.g., a benzyloxy or phenoxy group in the meta-position, are better suited for the sensitization of one-component diazotype material, even of such material that is developed with the weakly acid buffered developers, which are greatly preferred because of their high keeping quality.

Particularly attractive diazonium compounds are those according to the Formula IV in which X is an anion, R stands for a substituted or non-substituted alkyl group with at most 4 C-atoms, R for a substituted or non-substituted alkoxy group with at most 4 Catoms, R for a substituted or non-substituted phenyl group, R and R for substituted or non-substituted straight chain alkyl groups with at most 4 C-atoms. Diazotype material sensitized with these compounds has better keeping quality and higher developing speed than material which contains a diazonium compound according to the Formula III wherein Y is a halogen atom and R and R are alkyl groups. The said diazonium compounds according to the Formula III are used in practice on a large scale for sensitizing diazotype materials. Compared with these diazotype materials, the material of the present invention moreover yields copies which show a more attractive black azodyestuff image when a buffered weakly acid phloroglucinol developer is employed.

Equally attractive diazonium compounds are those according to the Formula IV in which X is an anion, R R and R stand for alkyl groups with at most 4 C-atoms, R for a substituted or non-substituted alkoxy, benzyloxy, or phenoxy group, and R for a cyclohexyl group.

Diazotype material sensitized with these compounds is also suitable for development with weakly acid buttered phloroglucinol developers and it also yields copies with fine black azo-dyestutf images, but in addition it is 15% more light-sensitive.

The following is a list, though not a complete one, of diazonium compounds which can be used with good results in diazotype material according to the invention:

4-diazo-3-N-methyl-N-formylamino-2-methoxy-N,N-

dimethylaniline 4-diazo-3-N-methyl-N-ethoxycarbonylamino-Z-methoxy- N,N-dimethylaniline 4-diazo-3-N-methyl-N-ethoxycarbonylamino-2,2'-ethoxyethoxy-N,N-dimethylaniline 4-diazo-3-N-methyl-N-ethoxycarbonylamino2-isobutoxy- N,N-dimethylaniline 4-diazo-3 -methyl-N-ethoxycarbonylamino-2-benzyloxy- N,N-dimethylaniline 4-diazo-3-N-methyl-N-ethoxycarbonylamino-Z-cyclopentoxy-N,N-dimethylaniline 4-diazo-3-N-methyl-N-ethoxycarbonylamino-Z-allyloxy- N,N-dimethylaniline 4-diazo-S-N-methyl-N-ethoxycarb onylamino-Z- (4-chlorophenoxy -N,N-dimethylaniline 4-diazo-3 -N-methyl-N-ethoxycarbonylamin-2-methoxy- N-methyl-N-cyclohexylaniline 4-diazo-3-N-methyl-N-ethoxycarbonylamino-2- (4'-chlorophenoxy -N-methyl-N-cyclohexylaniline 4-diazo-3-N-methyl-N-ethoxycarbonylamino-Z-methoxy- N-methyl-N-benzylaniline 4-diazo-3 -N-methyl-N-ethoxycarbonylamino-Z- 4'-chlorophenoxy -N,N-di (2'-ethoxycarbonyloxyethyl aniline 4-diazo-3 -Nmethy1-N-ethoxycarbonylamino-2-(4'-chlorophenoxy) -N,N-di 2'-chloroethyl) aniline 4-diazo-3-N-methyl-N-ethoxycarbonylamino-2-methoxy- N-cycloheXyl-N-benzylaniline 4-diazo-3-N- 2-diethylaminoethyl -N-ethoxycarbonylamino-Z-methoxy-N,N-dimethylaniline 4-diazo-3-N-n-propyl-N-ethoxycarbonylamino-Z-methoxy- N,N-dimethylaniline 4-diazo-3-N-isobutyl-N-ethoxycarbonylamino-2-methoxy- N,N-dimethylaniline 4-diazo-3-N-cyclohexyl-N-ethoxycarbonylamino-Z-methoxy-N,Ndimethylaniline 4-diazo-3benzyl-N-ethoxycarbonylamino-2-methoxy- N,N-dimethylaniline 4-diazo-3-N-methyl-N-2-chloroethyloxycarbonylamino-Z- methoxy-N,N-dimethylaniline 4-diazo-3 -N-methyl-N-cyclohexylcarbonylamino-Z-methoxy-N,N-dimethylaniline 4-diazo-3-N-methyl-N-benzyloxycarbonylamino-Z-methoxy-N,N-dimethylaniline 4-diazo-3-N-methyl-N-phenoxycarbonylamino-Z-methoxy- N,N-dimethylaniline 4-diazo-3 -N-methy1-N-acetylamino-2-methoxy-N,N-dimethylaniline 4-diazo-3-N-methyl-N-chloroacetylamino-2-methoxy-N,N-

dimethylaniline adipic acid di(N-methyl-N-Z'-diazo-5'-dimethylamino'6- methoxyphenylamide) 4diazo-3-N-methyl N-allyloxycarbonylamino- 2-methoxy-N,N-dimethylaniline 4-diazo-3-N-allyl-N-ethoxycarbonylamino-Z-methoxy- N,N-dimethylaniline 4-diazo-3-N-methyl-N-benzoylamino-2-methoxy-N,N-

dimethylaniline 4-diazo-3-N-methyl-N-isobutoxycarbonyl-2- (4'-chlorophenoxy) -N,N-dimethylaniline N- 4-diazo-3-N-methyl-N-ethoxycarbonylamino-2-methoxyphenyl) -morpholine N- 4-diazo-3-N-methyl-N-ethoxycarbonylamino-Z-methoxyphenyl) -N'-ethoxycarbonylpiperazine- 1,4.

The diazonium compounds can be used as diazonium salts, e.g. as diazonium chloride, sulfate, hydrogen sulfate or phosphate, or as metal chloride double salt, such as chlorozincate and chlorostannate, as diazonium borofluoride or as diazonium aryl sulfonate.

They can be applied in the diazotype material individually, mixed together, or in admixture with diazonium compounds of other types. It goes Without saying that as the diazotype material according to the invention has a higher content of another diazonium compound it will present the specific advantages of the diazonium compounds according to the invention to a lesser degree.

The familiar supports, such as paper, tracing paper, printing-plate paper, tracing linen, opaque linen, synthetic paper, metal sheets, glass fibres, polyester film and the like,

can be sensitized with the diazonium compounds according to the invention. The diazonium compound may or may not be incorporated in a hydrophilic or hydrophobic film layer, which, as desired, has been anchored to the support with the aid of one or more intermediate layers.

In the diazotype material according to the invention the conventional auxiliary agents can be used, e.g. acids, such as citric acid, tartaric acid, boric acid, and phosphoric acid; stabilizers, such as benzene and naphthalene sulfonic acids, p-phenolsulfonic acid, and their water-soluble salts; metal salts, such as zinc chloride magnesium chloride, nickel sulfate, and alum; substances which serve to enhance the developing speed, such as glycerol, polyethylene glycol, urea, thiosinamine, and the like; surface-improving substances such as finely divided silicon dioxide (colloidal or non-colloidal), aluminum oxide, barium sulfate, and rice starch; binders such as gelatin, gum arabic, cellulose ethers, starch derivatives, polyvinyl alcohol; dispersions of synthetic resins, such as dispersions of cationic, non-ionic, and anionic polyvinyl acetate.

The phloroglucinol developers which are used in the one-component diazotype process often vary as to their composition and acidity. Below, two Weakly acid phloroglucinol developers and one Weakly alkaline phloroglucinol developer are described which are employed in practice and are used for development in a number of the following examples.

Developer A is a solution of 4 g. of phloroglucinol 0.1 g. of acetoacetanilide 3 ml. of sodium 2-ethylhexyl sulfate 15 g. of beet sugar 2.5 g. of benzoic acid 14 g. of sodium benzoate 135 g. of sodium formate in 1000 ml. of water.

The pH of this liquid is approximately 5.8.

Developer B is a solution of:

6.5 g. of phloroglucinol 4 g. of resorcinol 10 g. of thiourea 2 g. of sodium dibutylnaphthalene sulfonate 14 g. of sodium formate 22 g. of sodium benzoate 49 g. of trisodium citrate (2 aq.)

1.2 g. of citric acid in 1000 ml. of water.

The pH of this liquid is approximately 6.5.

Developer C is a solution of:

30 g. of thiourea 5.4 g. of phloroglucinol 6.5 g. of resorcinol 1 g. of potassium hydroquinone monosulfonate 5 g. of sorbitol 15 g. of beet sugar 50 g. of potassium tetraborate (5 aq.)

1.5 g. of sodium isopropylnaphthalene sulfonate in 1000 ml. of water.

The pH of this liquid is approximately 9.

EXAMPLE I A stock solution of:

20 g. of the sodium salt of 2,7-dihydroxynaphthalene- 3,6-disulfonic acid 60 g. of tartaric acid, and

ml. of hydrochloric acid (s.g. 1.19) in 60 ml. of propanol-Z and 1900 ml. of water is prepared.

Two l-litre portions of the liquid are taken.

(A) In one of the portions is dissolved such a quantity of 4 dimethylamino-3-methoxy-Z-N-methyl-N-formylaminobenzene diazonium chloride, stannic chloride double salt, prepared as described below, that a solution of 0.04 mole of diazonium salt is obtained.

(B) With the other portion of the stock solution a solution of 0.04 mole of 4-dimethylamino-3-methoxybenzene diazonium chloride, zinc chloride double salt is prepared.

With each of the solutions white base paper for the diazotype process, of weight 80 g./m. is sensitized. The sheets are marked A and B respectively. A strip of each of the two sheets is imagewise exposed underneath an ink drawing on tracing paper until the diazonium compound underneath the image-free portions of the drawing has completely bleached out. The strips are then developed in ammonia vapour. The copy on the strip cut from sheet A shows a purple image on a white background. The copy on the strip cut from sheet B shows a light violet-brown image on a white background.

Another strip of the sheets A and B is stored, in a closed, moisture-tight wrapping as commonly used for diazotype material, for some tens of hours in a room in which a temperature of about 50 C. prevails. After this the strips are imagewise exposed underneath a transparent ink drawing until the diazonium compound underneath the image-free portions of the drawing has completely bleached out, and the strips are then developed in ammonia vapour. Strip A shows a strong purple image, image B shows a faint violet-brown image, both on a white background.

The diazonium compound used according to the invention was prepared as follows:

2,3-dichloronitrobenzene was converted into 3-chloro- Z-methoxynitrobenzene with sodium methanolate. The nitro group of this product was reduced to an amino group, which was tosylated. The 3-chloro-2-methoxy-N- tosylaniline was nitrated, methylated, and saponified. The 4-nitro-3-choloro-2-methoxy N methylaniline thus obtained, which melts at 128 C., was methylated again to 4 nitro-3-chloro 2 methoxy N,N dimethyl aniline.

The chlorine atom of this compound was replaced by a methylamino group and then the methylamino group was acylated with formic acid. From the 4-nitro-3-N-methyl- N-formyl-amino 2 methoxy-N,N-dimethylaniline the above-mentioned diazonium salt was prepared in the usual way by reduction and diazotization. The azo-dyestuff of this diazonium compound with 1-phenyl-3-methylpyrazolone-5 melts at 168 C.

EXAMPLE II A stock solution of:

80 g. of the ethanol amide of 2,4-dihydroxybenzoic acid and 60 g. of tartaric acid in 600 ml. of ethanol (96%) 1500 ml. of water is prepared.

Two 1- litre portions of the liquid are taken.

(A) In one of these portions is dissolved such a quan tity of 4-dimethylamino-3-methoxy-2 N methyl N-acetylaminobenzene diazonium chloride, zinc chloride double salt, prepared as described below, so that a solution of 0.04 mole of the diazonium salt is obtained.

(B) With the other portion of the stock solution a solution of 0.04 mole of 4-dimethylamino-3-methoxybenzene diazonium chloride, zinc chloride double salt is prepared.

With each of the solutions, sized natural tracing paper, of weight 80 g./m. is sensitized. The sheets are marked A and B respectively. A strip of each of the two sheets is imagewise exposed underneath an ink drawing on tracing paper until the diazonium compound underneath the image-free portions of the drawing has completely bleached out. Then the strips are developed in ammonia vapour. The copies show a strong brown image on a transparent background.

Another strip of the sheets A and B is stored, in a closed, moisture-tight wrapping as commonly used for diazotype material, for some tens of hours in a room in which a temperature of about C. prevails. After this the strips are imagewise exposed underneath a transparent ink drawing until the diazonium compound underneath the image-free portions of the drawing has completely bleached out. The strips are developed in ammonia vapour. Strip A shows a strong brown image, strip B shows a faint brown image on a transparent background.

The diazonium compound used according to the example was prepared as follows:

4-nitro-3-methylamino-2-methoxy-N,N-dimethylaniline, prepared as described in Example I, was converted into 4-nitro-3-N-methyl-N-acetylamino-Z methoxy N,N dimethylaniline with acetyl chloride. From this product the above-mentioned diazonium salt was obtained in the usual way by reduction and diazotization. The azo-dyestulf of this diazonium compound with 1-phenyl-3-methylpyrazolone-5 melts at 188 C.

EXAMPLE III A planographic paper printing plate of the type, Rotaprint C3 is sensitized with a solution containing:

30 g. of 4-N-methyl-N-cyclohexylamino 3 (4' chlorophenoxy) -2-N-methyl-N-ethoxycarb onylamino-benzene diazonium chloride, zinc chloride double salt 200 ml. of ethanol (96%) 800 ml. of water and dried.

The light-sensitive printing plate has excellent keeping quality. It is imagewise exposed underneath a transparent ink drawing until the diazonium compound underneath the image-free portions of the drawing has completely bleached out. The image on the printing plate is developed by moistening the image side of the plate with a solution of:

12 g. of phloroglucinol 11 g. of citric acid 87 g. of di-sodium phosphate 2 aq. in 1000 ml. of water.

Then the plate is sponged off with water.

The plate shows a black image, which absorbs ink quite selectively. From the plate 50 good offset prints can be made.

The diazonium compound obtained according to the example was prepared as follows:

2,3-dichloronitrobenzene was fused with 4-chlorophenol and potassium hydroxide. The 3-chloro-2-(4'-chlorophenoxy)nitrobenzene was reduced and tosylated to 3-chloro- 2-(4-chlorophenoxy)-N-p-tosylaniline. This product was methylated, saponified, and cyclohexylated to 3-chloro-2- (4-chlorophenoxy)-N-rnethyl-N cyclohexylaniline. This product was nitrated, its chlorine atom was replaced by a methylamino group and this group was acylated with ethyl chloromethanoate. From the 4-nitro-3-N-methyl-N- ethoxycarbonylamino-Z-(4'-chlorophenoxy)- N-methyl-N- cyclohexylaniline, which melts at 163-164 C., the abovementioned diazonium salt was obtained in the usual way by reduction and diazotization.

EXAMPLE IV (A) White base paper for the diazotype process, of weight g./m. is sensitized with a solution containing:

33 g. of 4-N-methyl-N-benzylamino 3 methoxy 2 N- methyl N ethoxycarbonylaminobenzene diazonium chloride, zinc chloride double salt 5 g. of tartaric acid 30 ml. of aqueous polyvinyl acetate dispersion Vinnapas H.60 (from Wacker-Chemie G.m.b.H., Munich, Germany) in 1000 ml. of water and dried.

(B) Another sheet of white base paper for the diazotype process of 80 g./rn. is sensitized with a solution containing:

32 g. of 4-N-methyl-N-cyclohexylamino 3 methoxy 2 N-methyl-N ethoxycarbonylaminobenzene diazonium chloride, zinc chloride double salt g. of tartaric acid 30 ml. of Vinnapas H60 in 1000 m1. of water,

and dried.

Approximately 0.42 millimole of diazonium compound per m? is present on both sheets. Both sheets are imagewise exposed underneath a transparent pencil drawing until the diazonium compound underneath the imagefree portions of the drawing has just bleached out on Sheet B. Then both sheets are developed with developer A.

The copy on sheet A shows a blue-black image on a foggy grey background. The copy on sheet B also shows a blue-black image, but, on a bright white, completely bleached-out background. The diazonium compound used in sensitizing liquid A is less light-sensitive than the compound used in sensitizing liquid B.

The new diazonium compounds used according to the example were prepared as follows:

(A) 4-nitro-3-chloro-2-methoxy-N-methylaniline, prepared in the way described in Example I, was benzylated. Then the chlorine atom was replaced with monomethy1 amine by a methylamino group, which was acylated with ethyl chloromethanoate. From the 4-nitro-3-N-methyl-N- ethoxycarbonylamino-2-methoxy-N-methyl-N benzylaniline the above-mentioned diazonium salt was obtained in the usual way by reduction and diazotization. The azodyestuff of this diazonium compound with 1-phenyl-3- methyl-pyrazolone-S melts at 164165 C.

(B) 3-chloro-2-methoxy -N tosylaniline was methylated, saponified and cyclohexylated. The 3 chloro-2- methoxy-N-methyl-N-cyclo-hexylaniline thus obtained was nitrated and then the chlorine atom was replaced with monoethylamine by a methylamino group, which was acylated with ethyl chloromethanoate. From the 4-nitro- 3-N-methyl-N-ethoxycarbonylamino 2 methoxy N methyl-N-cyclohexylaniline the diazonium salt was obtained in the usual way by reduction and diazotization. The azo-dyestuff of this diazonium compound with 1- phenyl-3-methylpyrazolone-5 melts at 155 C.

EXAMPLE V A dispersion of di(octadecylammonium)oxalate is prepared by grinding a mixture of:

g. of di(octadecylammonium)oxalate 1.5 g. of oxalic acid 4 g. of polyvinyl alcohol of the type Rhodoviol 4/20 P (from Rhone-Poulenc S.A., Paris, France) and 80 ml. of water for 20 hours in a ball-mill.

With the dispersion thus obtained a layer of approximately 6 g./m. dry weight is applied on white base paper for the diazotype process, of weight 70 m./m.

The paper thus pre-treated is sensitized with a solution containing:

14.7 g. of 4 dirnethylamino-3-isobutoxy-2-N-methyl-N- ethoxycarbonylaminobenzene diazonium chloride, stannic chloride double salt g. of the sodium salt of 2,7-dihydroxynaphthalene-3,6-

disulfonic acid 25 g. of oxalic acid g. of rice starch g. of polyvinyl alcohol (of the type Rhodoviol 4/ 20 P) 1 ml. of wetting agent on basis of polymerized ethylene oxide, Scurol 0 (from Rhone-Poulenc S.A.) in

1000 ml. of water and dried.

A sheet of the diazotype material thus obtained is imagewise exposed underneath a letter typed on one side until the diazonium compound underneath the image-free portions of the letter has completely bleached out. Then the sheet is developed by guiding it over a metal cylinder with a surface temperature of about C.

The copy shows a strong violet image on a foggy violet background.

If instead of the above-mentioned diazonium compound the corresponding compound without o-substituent had been used, copies would have been obtained with a dull violet-brown image. On account of the relatively great pyrolysis of the diazonium compound, which occurs during development, the image of the copy is markedly less intensive.

The diazonium compound used in the example Was prepared as follows:

2 methoxy 3 chloronitrobenzene was de-etherified and converted into 3-chloro-2-isobutoxynitrobenzene with isobutyl bromide. This product was reduced, tosylated, and nitrated. The 4 nitro-3-chloro-2- isobutoxy-N-tosylaniline was methylated, saponified, and methylated again. The chlorine atom of the 4 nitro-3-chloro-2-isobutoxy-N,N- dimethylaniline was replaced by a monomethylamino group, which was then acylated with ethyl chloromethanoate. From the 4 nitro-3-N-methyl N ethoxycarbonylamino 2 isobutoxy N,N-dimethylaniline the abovementioned diazonium salt was obtained in the usual way by reduction and diazotization. The azo-dyestuif of this diazonium compound with l-phenyl-3-methylpyrazolone-5 melts at 162 C.

EXAMPLE VI A solution of:

5 g. of citric acid in 30 ml. of isopropanol and 970 ml. of water is prepared.

Six l00-ml. portions of this solution are taken. To these portions is added respectively:

(A) 1.13 g. of 4-dimethylamino-3-methoxybenzene diazonium chloride, zinc chloride double salt (B) 1.53 g. of 4-dimethylamino-3-methoxy-2-N-methyl- N ethoxycarbonylaminobenzene diazonium chloride, zinc chloride double salt (C) 1.90 g. of 4 dimethylamino-3-methoxy 2-N-npropyl N ethoxycarbonylaminobenzene diazonium chloride, stannic chloride double salt (D) 1.95 g. of 4-dimethy1amino-3-methoxy-2-N-isobutyl N ethoxycarbonylaminobenzene diazonium chloride, stannic chloride double salt (E) 2.05 g. of 4-dimethylamino-3-methoxy-2-N-cyclohexyl-N-ethoxycarbonylaminobenzene diazonium chloride, stannic chloride double salt (F) 1.83 g. of 4-dimethylamino-3-methoxy-2-N benzyl- N ethoxycarbonylaminobenzene diazonium chloride, zinc chloride double salt.

With each solution a sheet of white base paper for the diazotype process which has been pre-treated with noncolloidal silica is sensitized in such a way that the paper contains approximately 0.5 millimole of diazonium com pound per m and dried until the paper has a moisturecontent of approximately 3%. The light-sensitive papers obtained have practically the same light-sensitivity. A first strip of them is image'wise exposed underneath a transparent pencil drawing until the diazonium compound underneath the image-free portions of the drawing has almost completely bleached out. Then they are developed with developer B. The copy on sheet A shows hardly any development. The other copies develop rapidly in consequence of the much higher coupling activity of the diazonium compounds. The copy on sheet B shows a very dark violet-brown image on a foggy violet-brown back 1 1 ground. The copies on the sheets C and D show a black image on a foggy brown-grey background. The copies on the sheets E and F show a black image on a foggy bluegrey background.

A second strip of the sheets A, B, C, D, E, and F is stored for some days in a moisture-tight wrapping at a temperature of 50 C. Then the strips are imagewise exposed underneath a transparent ink drawing until the diazonium compound underneath the image-free portions of the drawing has completely bleached out. The strips are then developed with developer C, with which paper A also gives complete development.

The strips B, C, D, E, and F show a much more intensive image than strip A because a large part of the diazonium compound on strip A has decomposed during storage.

The diazonium compounds according to the invention used in the example were prepared as follows:

4 nitro 3 chloro-2-methoxy-N,N-dimethylaniline prepared as described in Example I was brought into reaction With methylamine and then aeylated with ethyl chloromethanoate. 4-dimethylamino-3-methoxy 2 N- methyl N ethoxycarbonylamino nitrobenzene was obtained. 4 nitro-3-chloro-2-methoxy-N,N-dimethylaniline was brought into reaction with n-propylamine and then aeylated with ethyl chloromethanoate. 4 dimethylamino- 3-methoxy-2-N-n-propyl N ethoxycarbonylaminonitrobenzene was obtained. 4 nitro-3-chloro-2-methoxy N,N- dimethylaniline was brought into reaction with isobutylamine and then aeylated with ethyl chloromethanoate. 4 dimethylamino 3 methoxy-Z-n-isobutyl-N-ethoxycarbonylaminonitrobenzene 'was obtained 4-nitro-3-chloro-2- methoxy-N,N-dimethylaniline was brought into reaction with cyclohexylamine and then aeylated with ethyl chloromethanoate. 4 dimethylamino-3-methoxy-2-N-cyclohexyl-N-ethoxycarbonylaminonitrobenzene was obtained. 4 nitro 3 chloro 2 methoXy-N,N-dimethylaniline was brought into reaction with benzylamine and then aeylated with ethyl chloromethanoate. 4 dimethylamino-3-methoxy-Z-N-benzyl N ethoxycarbonylaminonitrobenzene was obtained, which melts at 82- 83 C.

From the nitrobenzene compounds prepared as described above the above-mentioned diazonium salts were obtained in the usual way by reduction and diazotization.

The azo-dyestuff of 1-phenyl-3-methylpyrazolone-5 and the 4 dimethylamino-3-methoxy-2-N-methyl-N-ethoxycar-bonylamino benzene diazonium compound melts at 147 C., the azo-dyestulr' of 1-phenyl-3-methylpyrazolone- 5 and the 4 dimethylamino 3-rnethoxy-2-N-n-propyl- N ethoxycarbonylaminobenzene diazonium compound melts at 130 C., the azo-dyestutf of 1-phenyl-3-methylpyrazolone-S and the 4-dimethylamino-3-methoxy-2-N- isobutyl-N-ethoxycarbonylaminobenzene diazonium compound melts at 102104 C., the azo-dyestulf of l-phenyl- 3-methyl-pyrazolone-5 and the 4-dimethylamino-3-methoxy 2-N-cyclohexyl-N-ethoxycarbonylaminobenzene diazonium compound melts at 164 C.

EXAMPLE VII A solution of:

5 g. of citric acid in 30 ml. of isopropanol and 970 ml. of water is prepared.

Six 100-ml. portions of this solution are taken. To these portions is added respectively:

(A) 1.13 g. of 4-dimethylamino-3-methoxybenzene diazonium chloride, zinc chloride double salt (B) 1.53 g. of 4-dimethylamino-3-methoxy-2-N-methyl- N-ethoxycarbonylamino-benzene diazonium chloride, zinc chloride double salt (C) 1.91 g. of 4-dimethylamino-3-methoxy-2-N-methyl- N-benzoylaminobenzene diazonium chloride, stannic chloride double salt 12 (D) 1.97 g. of 4-dimethylamino-3-methoxy-2-N-methyl- N-phenoxycarbonylaminobenzene diazonium chloride, stannic chloride double salt (E) 2.03 g. of 4-dimethylamino-3-methoxy-2-N-methyl- N-benzyloxycarbonylaminobenzene diazonium chloride, stannic chloride double salt (F) 1.92 g. of 4-dimethylamino-3-methoxy-2-N-methy1- N 2' chloroethoxycarbonylaminobenzene diazonium chloride, stannic chloride double salt.

With each of the solutions a sheet of white base paper for the diazotype process, pre-treated with non-colloidal silica is sensitized in such a way that each paper contains about 0.5 millimole of diazonium compound per m. and dried until the paper has a moisture-content of about 3% All the light-sensitive papers thus obtained are very lightsensitive. A first strip of them is imagewise exposed underneath a transparent pencil drawing until the diazoniurn compound underneath the image-free portions of the drawing has almost completely bleached out. Then they are developed with developer B. The copy on sheet A hardly develops. Each of the copies on the sheets B, C, D, E, and F shows a strong, very dark, almost black azodyestuff image on a more or less gray background.

A second strip of the sheets A, B, C, D, E, and F is stored for some days in a moisture-tight wrapping at a temperature of C. Then the strips are imagewise exposed underneath a transparent ink drawing until the diazonium compound underneath the image-free portions of the drawing has completely bleached out. The strips are then developed with developer C, with which paper A also gives complete development.

The strips B, C, D, E, and F show a much more intensive image than strip A because a large part of the diazonium compound on strip A has decomposed during storage.

The diazonium compounds C, D, E, and F were prepared as follows:

4 dimethylamino 3 methoxy-Z-methylaminonitrobenzene was acylated with benzoylchloride, phenyl chloromethanoate, benzyl chloromethanoate, and 2-chloroethyl chloromethanoate respectively. The substances obtained were, respectively:

4 dimethylamino 3 methoxy-2-N-methyl-N-benzoylaminonitrobenzene, which melts at 112-113 C.,

4 dimethylamino 3 methoxy-2-N-methyl-N-phenoxycarbonylaminonitrobenzene, which melts at 110- 111 C.,

4 dimethylamino 3 methoxy-Z-N-methyl-N-benzyloxycarbonylaminonitrobenzene, which melts at 93- 94 C.,

4 dimethylamino 3 methoxy-2-N-methyl-N-2'-chloroethoxycarbonylaminonitrobenzene, which melts at 73- 74 C.

From these nitro compounds the diazonium salts were obtained in the usual way by reduction and diazotization.

EXAMPLE VIII White base paper for the diazotype process, of weight 50 g./m. was sensitized with a solution containing:

25 g. of 4-morpholino-3-methoxy-2-N-methyl-N-ethoxycarbonylaminobenzene diazonium chloride, stannic chloride double salt 5 g. of tartaric acid 20 g. of sodium naphthalene-l,3,6-trisulfonate 30 ml. of aqueous polyvinyl acetate dispersion Vinnapas H in 1000 m1. of water and dried.

A sheet of the diazotype paper thus obtained is imagewise exposed underneath a transparent ink drawing until the diazonium compound underneath the image-free portions of the drawing has almost completely bleached out, and then developed with developer C.

The copy shows a brown image on a white background. The copy is quite suitable as an intermediate for making further copies on diazotype paper.

The diazonium compound used in the example was prepared as follows:

4 nitro-3-chloro-2-methoxy-N-t0sylaniline, prepared as described in Example I, was saponified and then diazotized and converted into 2,4-dichloro-S-methoxynitrobenzene according to Sandmeyer. The chloride atom in the 2- position of this compound was replaced by a methylamino group. The 4-chloro-3-methoxy-2-methylaminonitrobenzene thus obtained, which melts at 70 C., was brought into reaction with morpholine and then acylated with ethyl chloromethanoate. From the 4-morpholino-3-methoxy-2-N-methyl-N-ethoxycarbonylaminonitrobenzene thus obtained, the above-mentioned diazonium salt was pre pared in the usual way by reduction and diazotization. The azo-dyestutf of 1-phenyl-3-methylpyrazolone-5 and this diazonium compound melts at 193-l97 C.

EXAMPLE IX Three sensitizing liquids are prepared, the liquids containing, respectively:

13 g. of 4-dimethylamino-3-benzyloxybenzene diazonium chloride, zinc chloride double salt g. of tartaric acid 300 ml. of ethanol 700 ml. of water.

16 g. of 4-dimethylamino-3-benzyloxy-2-N-methyl-N- ethoxycarbonylaminobenzene diazonium chloride, stannic chloride double salt 5 g. of tartaric acid 300 ml. of ethanol 700 m1. of water.

14.5 g. of 4-dimethylamino-3-allyloxy-2-N-methyl-N- ethoxycarbonylaminobenzene diazonium chloride, stannic chloride double salt 5 g. of tartaric acid 300 ml. of ethanol 700 ml. of water.

With each of the liquids a sheet of opaque linen for reproduction purposes is sensitized in such a way that, after drying, each of the sheets, marked A, B, and C respectively, contains approximately 0.45 millimole of diazonium compound per m.

A strip of each sheet is imagewise exposed underneath a transparent ink drawing until the diazonium compound underneath the image-free portions of the drawing has just completely bleached out. It appears that the three sheets have practically the same light-sensitivity.

Then the strips are developed with developer B. The copies on the strips B and C develop more rapidly than the copy on strip A. The copy on strip A shows a dark violet-brown image on a white background, the copies on the strips B and C show a black image on a white background.

Another strip of each sheet is stored for some days in a moisture-tight wrapping at 50 C. Then the strips are imagewise exposed until underneath the image-free portions of the original the diazonium compound has completely bleached out, and subsequently they are developed with developer C. Strip A shows a less intensive azo-dyestuff image than the strips B and C in consequence of the pyrolysis of the diazonium compound during storage.

The diazonium compounds B and C used in the example were prepared as follows:

Z-methoxy-3-chloronitrobenzene was de'etherified and converted with benzyl bromide into 3-chloro-2-benzyloxynitrobenzene. This product was reduced, methylated, and nitrated. The chlorine atom of the 4-nitro-3-chloro-2-benzyloxy-N,N-dimethylaniline thus obtained was replaced by a methylamino group, which was then acylated with ethyl chloromethanoate. From the 4-nitro-3-N-methyl-N- ethoxycarbonylamino 2 benzyloxy N,N dimethylaniline the above-mentioned diazonium salt was prepared in the usual way by reduction and diazotization. The azodyestuif of this diazonium compound with 1-phenyl-3- methylpyrazolone-S melts at l51l52 C.

Diazonium compound C was prepared in an analogous way. The 4-nitro-3-N-methyl-N-ethoxycarbonylamino-Z- allyloxy-N,N-dimethylaniline, from which the abovementioned diazonium salt was prepared, melts at 84 C.

EXAMPLE X White paper of weight g./m. coated on one side with a cellulose acetate film layer (approximately 50% by weight of combined acetic acid) having a thickness of approximately 10 microns, which layer has been affixed to the paper by means of an adhesive and has been deacylated to a depth of about 4 microns to an average acetyl content, calculated as combined acetic acid, of approximately 20% by weight (which corresponds to an average number of acyl groups per glucose unit of the cellulose acetate of 0.7), is impregnated on the de-acylated side of the cellulose acetate layer with the following solution:

68 g. of 4-N,N-bis-(2'-ethoxycarbonyloxyethyl)amino-3- (4'-chlorophenoxy) 2 N-methyl-N-ethoxycarbonylaminobenzene diazonium chloride, zinc chloride double salt 5 g. of tartaric acid 300 ml. of ethanol (96%) 700 ml. of water and dried.

The diazotype material thus obtained is very light-sensitive. A sheet of this material is imagewise exposed underneath a transparent ink drawing until the diazonium compound underneath the image-free portions of the drawing has completely bleached out, and is then developed with developer A.

The copy shows a black image on a bright white background.

The diazonium compound used in the example was prepared as follows:

2,3-dichloronitrobenzene was fused with 4-chlorophe- 1101 and potassium hydroxide. The 3-chloro-2-(4'-chloro phenoxy)nitrobenzene was reduced and then brought into reaction with epoxyethane. The 3-chloro-2-(4'-chlorophenoxy)-N,N-di(2'-hydroxyethyl)aniline thus obtained was acetylated, nitrated, and deacetylated. The 4-nitro-3- chloro-2- 4-chlorophenoxy -N,N-di 2'-hydroxyethyl) aniline thus prepared was then converted with monomethylamine into 4-nitro-3-methylamino-2-(4'-chlorophenoxy)- N,N-di(2-hydroxyethyl)aniline. This product was acylated with ethyl chloromethanoate. From the 4-N,N-bis (2-ethoxycarbonyloxyethyl)amino 3 (4'-chlorophenoxy)-2-N-methyl N ethoxycarbonylaminonitrobenzene thus obtained, which melts at 76 C., the above diazonium salt was obtained in the usual way by reduction and diazotization.

As used in the claims, the term alkyl and its equivalent in alkoxy, where not otherwise qualified inconsistently with the meaning here given, is meant to include non-branched, branched, saturated and/or unsaturated monovalent groups, or radicals, derived from aliphatic hydrocarbons, in any of which one or more of the hydrogen atoms normally present may have been replaced by a substituent suitable for light-sensitive diazonium compounds, such as a halogen atom, an amino group, an alkoxy group, or some other. Similarly, the terms cycloalkyl, aralkyl, aryl, cycloalkoxy, aralkoxy and aryloxy are meant to include groups, or radicals, of the character respectively denoted by these terms, in any of 15 which one or more of the hydrogen atoms normally present may have been replaced by such a substituent.

What is claimed is: 1. A light-sensitive diazonium compound of the general formula in which:

X is an anion;

R is alkyl, cycloalkyl or aralkyl;

R is a hydrogen atom or an alkyl, cycloalkyl, aralkyl, aryl, alkoxy, cycloalkoxy, aralkoxy or aryloxy radical;

R is alkyl, cycloalkyl, aralkyl or aryl;

R is alkyl or aralkyl; and

R is akyl, cycloalkyl or aralkyl; or

is a fiveor siX-membered heterocyclic ring attached by a nitrogen atom forming part of the ring to the phenyl nucleus carrying the diazonium group. 2. A light-sensitive diazonium compound of the formula in which:

X is an anion;

R is an alkyl group having 1-4 C atoms or a cycloalkyl or a benzyl group;

R is hydrogen, an alkyl or alkoxy group having 1 to 4 C atoms, or a cycloalkyl, benzyl, phenyl, benzyloxy, or phenyloxy group;

R is an alkyl group having 1-4 C atoms of a cycloalkyl, benzyl, or phenyl group;

R is an alkyl group having 1-4 C atoms, a benzyl group or an alkoxycarbonyloxyalkyl group having more than 4 C atoms, and

R is an alkyl group having 1-4 C atoms, a cycloalkyl or benzyl group, or an alkoxycarbonyloxyalkyl group having more than 4 C atoms; or

R and R together with the nitrogen atom by which they attach to the phenyl nucleus carrying the diazonium group constitute a morpholino, piperazino, piperidino or pyrrolidino ring.

3. A diazonium compound according to claim 1, wherein:

R is alkyl, aralkl or cycloalkyl.

4. A diazonium compound according to claim 1,

wherein:

R is an alkyl group having at most 4 C-atoms;

R is an alkoxy group having at most 4 C-atoms;

R is a phenyl group; and

R and R each is a straight chain alkyl group having at most 4 C-atoms.

5. A diazonium compound according to claim 1, wherein:

R R and R each is an alkyl group having at most 4 C-atoms;

R is an alkoxy group having at most 4 C-atoms, or a benzyloxy or phenoxy group; and R is a cyclohexyl group.

6. A diazonium compound according to claim 1, namely, a 4 N,N dialkylamino-3-alkoxy-2-N-alkyl-N- alkoxy-carbonylamino benzene diazonium compound.

7. A diazonium compound according to claim 1, namely, a 4 N,N dimethylamino-3-alkoxy-2-N-benzyl- N-ethoXy-carbonylamino benzene diazonium compound.

8. A diazonium compound according to claim 1, namely, a 4 N,N-dimethylamino-3-alkoXy-2-N-allyl-N- ethoxy-carbonylamino benzene diazonium compound.

9. A diazonium compound according to claim 1, namely, a 4 N methyl-N-cyclohexylamino-3-alkoxy-2- N alkyl N ethoxycarbonylamino benzene diazonium compound.

10. A diazonium compound according to claim 1, namely, a 4 N,N dialkylamino-3-chlorophenoxy-2-N- methyl-N-ethoxycarbonylamino benzene diazonium compound.

11. A diazotype material comprising a support carrying a light-sensitive layer containing a diazonium compound as defined in claim 1.

12. A diazotype material comprising a support carrying a light-sensitve layer containing a diazonium compound according to claim 1.

13. A diazotype material comprising a support carrying a light-sensitve layer containing a diazonium compound according to claim 2.

14. A one-component diazotype material comprising a support carrying a light-sensitive layer containing, in the substantial absence of an azo coupling component, a diazonium compound according to claim 1, wherein:

R is an alkyl group having at most 4 C-atoms;

R is an alkoxy group having at most 4 C-atoms;

R is a phenyl group; and

R and R each is a straight chain alkyl group having at most 4 C-atoms.

15. A one-component diazotype material comprising a support carrying a light-sensitive layer containing, in the substantial absence of an azo coupling component, a diazonium compound according to claim 1, wherein, in the said formula:

R R and R each is an alkyl group having at most 4 C-atoms;

R is an alkoxy group having at most 4 C-atoms, or a benzyloxy or phenoxy group; and R is a cyclohexyl group.

16. A one-component diazotype material comprising a support carrying a light-sensitive layer containing, in the substantial absence of an azo coupling component, a diazonium compound as defined in claim 6.

17. a one-component diazotype material comprising a support carrying a light-sensitive layer containing, in the substantial absence of an azo coupling component, a diazonium compound as defined in claim 5.

18. A one-component diazotype material comprising a support carrying a light-sensitive layer containing, in the substantial absence of an azo coupling component, a diazonium compound as defined in claim 8.

19. A one-component diazotype material comprising a support carrying a light-sensitive layer containing, in the substantial absence of an azo coupling component, a diazonium compound as defined in claim 9.

1 7 1 8 20. A one-component diazotype material comprising FOREIGN PATENTS a support carrying a light-sensitve layer containing, in the 6 407 303 1/1965 Netherlands substantial absence of an azo coupling component, a 1005:899 9/1965 Great Britai'n.

diazonium compound as defined in claim 10.

References Cited 5 NORMAN G. TORCHIN, Primary Examlner UNITED STATES PATENTS C. BOWERS, Assistant Examlner 3,028,240 4/1962 Werner et a1. 96-91 3,311,475 3/1967 Van Loon et a1. 9691 260141;9649 3,338,713 8/1967 Hendrickx et a1. 96-91 10 

